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EXPLORING PSYCHOLOGY(7th Edition in Modules)

David MyersPowerPoint Slides

Aneeq AhmadHenderson State

University

Worth Publishers, © 2008

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The Brain

Module 4

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The Brain: Older Brain Structures

The Brainstem is the oldest part of the brain, beginning where the spinal cord swells and enters the skull. It is responsible for automatic survival

functions.

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Brainstem

The Medulla [muh-DUL-uh] is the base

of the brainstem that controls heartbeat

and breathing.

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Brainstem

The Thalamus [THAL-uh-muss] is the brain’s sensory switchboard, located on top of the brainstem. It directs

messages to the sensory areas in the cortex and transmits

replies to the cerebellum and

medulla.

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Brainstem

Reticular Formation is a nerve network in the brainstem that plays an important role in controlling

arousal.

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The “little brain” attached to the rear of the brainstem. It

helps coordinate voluntary movements

and balance.

Cerebellum

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The Brain

Techniques to Study the Brain

A brain lesion experimentally

destroys brain tissue to study animal behaviors after such destruction.

Hubel (1990)

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Clinical ObservationClinical observations have shed light on a

number of brain disorders. Alterations in brain morphology due to neurological and

psychiatric diseases are now being catalogued.

Tom

Landers/ B

oston Globe

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Electroencephalogram (EEG)An amplified recording of the electrical waves

sweeping across the brain’s surface, measured by electrodes placed on the scalp.

AJ P

hoto/ Photo R

esearchers, Inc.

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PET Scan

PET (positron emission tomography)

Scan is a visual display of brain

activity that detects a radioactive form of glucose while the

brain performs a given task.

Courtesy of N

ational Brookhaven N

ational Laboratories

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MRI ScanMRI (magnetic

resonance imaging) uses magnetic fields and

radio waves to produce computer-generated

images that distinguish among different types of brain tissue. Top images

show ventricular enlargement in a

schizophrenic patient. Bottom image shows brain regions when a

participants lies.

Both photos from Daniel Weinberger, M.D., CBDB, NIMH

James Salzano/ Salzano Photo Lucy Reading/ Lucy Illustrations

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The Limbic System is a doughnut-shaped system of neural

structures at the border of the brainstem and cerebrum, associated with emotions such as fear, aggression and

drives for food and sex. It includes the hippocampus, amygdala, and hypothalamus.

The Limbic System

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Amygdala

The Amygdala [ah-MIG-dah-la] consists of two lima bean-sized neural clusters linked to the emotions of fear and

anger.

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Hypothalamus

The Hypothalamus lies below (hypo) the thalamus. It directs several maintenance activities like eating,

drinking, body temperature, and

control of emotions. It helps govern the

endocrine system via the pituitary gland.

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Rats cross an electrified grid for self-

stimulation when electrodes are placed

in the reward (hypothalamus) center (top picture). When the

limbic system is manipulated, a rat will navigate fields or climb

up a tree (bottom picture).

Reward CenterS

anjiv Talw

ar, SU

NY

Dow

nstate

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The Cerebral Cortex

The intricate fabric of interconnected neural cells that covers the cerebral hemispheres. It is the body’s ultimate control and information processing center.

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Structure of the Cortex

Each brain hemisphere is divided into four

lobes that are separated by

prominent fissures. These lobes are the

frontal lobe (forehead), parietal lobe (top to rear head), occipital lobe (back head) and temporal lobe (side of

head).

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Functions of the Cortex

The Motor Cortex is the area at the rear of the frontal lobes that control voluntary movements. The Sensory Cortex (parietal cortex) receives

information from skin surface and sense organs.

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Visual Function

The functional MRI scan shows the visual cortex is active as the subject looks at faces.

Courtesy of V

.P. Clark, K

. Keill, J. M

a. M

aisog, S. Courtney, L

.G.

Ungerleider, and J.V

. Haxby,

National Institute of M

ental Health

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Auditory Function

The functional MRI scan shows the

auditory cortex is active in patients who

hallucinate.

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More intelligent animals have increased “uncommitted” or association areas of the

cortex.

Association Areas

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LanguageAphasia is an impairment of language, usually caused by left hemisphere damage either to

Broca’s area (impaired speaking) or to Wernicke’s area (impaired understanding).

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Specialization & Integration

Brain activity when hearing, seeing, and speaking words

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The brain is sculpted by our genes but also by our experiences.

Plasticity refers to the brain’s ability to modify itself after some types of injury or illness.

The Brain’s Plasticity

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Our Divided Brain

Our brain is divided into two hemispheres. The left hemisphere processes reading,

writing, speaking, mathematics, and comprehension skills. In the 1960s, it was

termed as the dominant brain.

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Splitting the BrainA procedure in which the two hemispheres of the brain are isolated by cutting the connecting fibers

(mainly those of the corpus callosum) between them.

Corpus Callosum

Ma

rtin M

. Ro

the

r

Courtesy of T

erence William

s, University of Iow

a

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Split Brain Patients

With the corpus callosum severed, objects (apple) presented in the right visual field can be named.

Objects (pencil) in the left visual field cannot.

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Divided Consciousness

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Try This!

Try drawing one shape with your left hand and one with your right hand, simultaneously.

BB

C

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Non-Split Brains

People with intact brains also show left-right hemispheric differences in mental abilities.

A number of brain scan studies show normal individuals engage their right brain when completing a perceptual task and their left brain when carrying out a linguistic task.